MAZDA MX3 DENT PROBLEM

2006 Mazda MX3 • 9 miles

I have 2006 model mazda 3. When we star the car the acceleration will be above 5 rmp and also it will not down. Suddenly changing to Drive and moving. Even moving time acceleration will stuck and will not down and by the break I am controlling the car. While stopping after breaking suddently change to parking and switch off these procedure I am doing. (Even after changing gear to parking/nutral rpm/acceleration will be high and not under control)
Please advice me how solve this issue and how much cost will come for maintenance.